1. Field of the Invention
The present invention relates generally to an auger for removing grain from a storage bin and, particularly, to a sweep auger attachment pivotally mounted on an unloading conveyor to draw grain from the outer edges of the bin to a loading end of the unloading conveyor.
2. Description of the Prior Art
Various types of conveyors have been developed for removing grain or other material from bins, tanks or platforms. U.S. Pat. No. 2,393,572 to Soma and U.S. Pat. No. 1,564,187 to Ahrens disclose conveyors having an open auger universally joined to an enclosed auger. The open auger is manually moved around a bin to engage and convey material to the enclosed auger, which transports the material out of the bin. Movement of the open auger about the bin is limited by the universal joint connection, requiring periodic repositioning of enclosed auger to completely clean the bin.
U.S. Pat. No. 3,381,802 to Levadney, et al. describes a conveyor having a first horizontally disposed auger universally joined to a second auger held in a fixed angular relation with respect to the first auger. U.S. Pat. No. 2,058,125 to Bean discloses a freight car unloading conveyor having a plurality of universally joined augers universally connected to a movable base. Both the Levadney et al. and Bean conveyors must be continually manipulated into engagement with the material to be moved.
U.S. Pat. No. 2,790,563 to McCarthy, U.S. Pat. No. 2,711,814 to McCarthy and U.S. Pat. No. 2,763,362 to Greaves describe auger arrangements for removing grain from circular storage bins. The Greaves conveyor apparatus includes a plurality of augers universally joined together in tandem. The augers are initially positioned diametrically across the grain bin and are gradually moved to one side of the bin, removing the grain or other material from the bin as they move. The auger sections are also folded as they move to approximate the shape of the inner wall of the storage bin. When half of the bin has been cleaned in such a manner, the auger sections are repositioned at the center of the bin and rotated to the other side of the bin.
The apparatus described in McCarthy U.S. Pat. No. 2,790,563 comprises two independently driven auger mechanisms mounted to a turnplate mechanism. One auger mechanism is mounted on the storage bin wall and projects into the storage bin. A second auger mechanism rotates about the turnplate mechanism to draw the grain at the outer edges of the bin to the first auger mechanism which in turn draws the grain to an opening in the floor of the bin. McCarthy U.S. Pat. No. 2,711,814 describes a conveyor having an auger pivotally mounted to a pivot support extending through an opening in the floor of a bin. The auger rotates about the pivot support in the bottom of the tank, conveying grain to the opening. Both McCarthy conveyors are limited to use with bins having such openings in their floors.
U.S. Pat. No. 3,114,575 to Klein describes a jointed conveyor connecting a swing hopper to the lower end of an auger elevator. U.S. Pat. No. 3,331,640 to Prentice describes a silo unloader which utilizes an auger to convey material to a blower mechanism, which in turn propels the material out of the silo. U.S. Pat. No. 2,662,634 to Tintes describes an auxiliary conveyor attachment mounted on a conventional elevator conveyor which extends the location of a material receiving hopper.